The intensive introduction of advanced composites in primary structures has become a fundamental process of structural optimization (based on weight savings and the improvement of mechanical properties), one of the top priorities in the design and manufacture of a new generation of aircrafts. The introduction of an effective structural monitoring system capable of predicting the failure of load paths in a structure designed according to damage tolerance criteria would allow optimizing its design and, accordingly, reducing its weight.
Optical fiber sensors can be effectively used to measure thermomechanical deformation and even to detect damage events operating both alone in passive structural monitoring systems and in combination with other devices, forming active monitoring systems. One of their main advantages is their capacity to be embedded in composite structures, being intimately integrated into the structures.
However, one of the drawbacks of this integration is the difficulty that the repair of these optical fiber lines has once they are embedded. Optical fiber has extremely small dimensions and is fragile in handling with the tools normally used in repairing composites, therefore the possibilities of accessing it once it is embedded are very slim. This is incompatible with the reparability requirements needed when the structural health and maintenance criteria are bound to the correct working of the network of sensors integrated in the structure.
The present invention is aimed at solving this drawback.